In an Initial State, Follow, or Launch segment, you can define the fuel tank and other spacecraft physical values using the Spacecraft Parameters and Fuel Tank tabs. You can also change most of these properties at a later point in the space mission scenario in an Update segment.
Spacecraft Parameters
The following table defines the parameters on the Spacecraft Parameters tab:
| Field | Description |
|---|---|
| Dry Mass | The mass of the spacecraft exclusive of propellant. Enter a value in the selected mass unit (e.g. kg). |
| Drag Area | The cross-sectional area of the spacecraft assumed perpendicular to the direction of motion, used for atmospheric drag calculations. Enter a value in the selected distance unit squared. |
| Drag Coefficient (Cd) | The dimensionless drag coefficient associated with the drag area. |
| Solar Radiation Pressure (Spherical) Area | The cross-sectional area of the spacecraft assumed perpendicular to the direction of solar radiation, used for solar radiation calculations. Enter a value in the selected distance unit squared. |
| Solar Radiation Pressure (Spherical) Coefficient (Cr) | The reflectivity of the spacecraft used for solar radiation pressure calculations, where 2.0 is fully reflective and 1.0 is not reflective at all. |
| Radiation Pressure (Albedo/Thermal) Area | The cross-sectional area of the spacecraft assumed perpendicular to the direction of central body radiation, used for central body radiation (albedo / thermal pressure) calculations. Enter a value in the selected distance unit squared. |
| Radiation Pressure (Albedo/Thermal) Coefficient (Ck) | The reflectivity of the spacecraft used for central body radiation pressure (albedo / thermal pressure) calculations, where 2.0 is fully reflective and 1.0 is not reflective at all. |
| GPS Solar Radiation Pressure K1 | If you are using a non-spherical SRP model, this field defines the model's K1 (scale) value. |
| GPS Solar Radiation Pressure K2 | If you are using a non-spherical SRP model, this field defines the model's K2 (Y bias) value. |
Fuel Tank Configuration
The Fuel Tank tab is comprised of parameters defined in the following table:
| Field | Description |
|---|---|
| Tank Pressure | The fuel tank pressure. Enter a value in the selected pressure unit (e.g. Pa). |
| Tank Volume | The volume of the fuel tank. Enter a value in the selected distance unit cubed (e.g. m^3). The minimum value is 1e-019 m^3. |
| Tank Temperature | The temperature of the fuel tank. Enter a value in the selected temperature unit. |
| Fuel Density | The density of the fuel. Enter a value in the selected mass unit per the selected distance unit cubed (e.g. kg/m^3). |
| Fuel Mass | The mass of the spacecraft propellant. Enter a value in the selected mass unit (e.g. kg). |
| Maximum Fuel Mass | The maximum fuel mass of the spacecraft. This parameter specifically applies to Finite Maneuver segments that execute in Backward Sequences. Enter a value in the selected mass unit (e.g. kg). |
The Tank Volume and Maximum Fuel Mass parameters are related to the actual satellite object, and are not state values. So, you cannot edit either of these parameters when defining custom MCS segments using the Component Browser; they remain set to their default values and can only be modified within the MCS.